2.90.1 Vertices Keep Hiding, Unable to Weight Paint Mask
After going into sculpting mode and pressing Alt + H, it seems to have fixed the issue.
I did this because sculpt and weight paint had the same issue. Wouldn't let me touch the coat. I could sculpt and paint the sleeves, but only the sleeves.
It works now after that. I don't know why that fixed it, but it did.
For now.